| |
Meiosis Stages - The Eight Steps of Meiosis Explained
By Eugene M. McCarthy, Ph.D. Genetics - All rights reserved
See more about: meiosis stages mitosis stages interkinesis mitosis vs. meiosis chromosome structure
This is the first of several pages explaining and diagramming the eight stages of meiosis. Meiosis is the two-stage form of cell division that produces four haploid cells from a single diploid cell. This process divides a single nucleus (see figure right), containing two sets of replicated chromosomes (i.e., ones composed of two sister chromatids), into four nuclei, each containing a single set of unreplicated chromosomes.*
Now, if you already know the answers to the two questions in the green box below, go to the next page for a description of prophase I, the first stage of meiosis.
NEXT PAGE >>
TWO COMMON QUESTIONS:
When does meiosis occur? Meiosis occurs only in eukaryotes. In animals, it occurs during the production of gametes. In plants, it takes place when spores are produced (plant gametes are produced by mitosis). Meiosis does not occur in prokaryotes (i.e., archaea and bacteria). They reproduce by binary fission.
Why is meiosis necessary? Meiosis has to take place at some point in a sexual reproductive cycle because it halves the chromosome number, which compensates for the doubling of the chromosome number caused by fertilization.
|
|
* An exception is the case of oogenesis, where a single egg cell and three polar bodies are produced by meiosis.
|
|
Eukaryotic Nucleus:
(click on words in figure to see their definitions)
|
 |
|
| Meiosis Stages - Macroevolution.net |
| If you find any factual error or typo on this website, it will be greatly appreciated if you send in a message about the mistake. Please use the Contact Page, which lets you remain anonymous if you wish. Thank you. |
Disclaimer: Although every effort has been made to ensure the accuracy of the information presented on this website, Macroevolution.net and its maintainers cannot be held responsible for the accuracy of the information contained in the pages of this site, nor for any actions made on the basis of information provided by this website.
|
|
